B235r weak pistons?

jmichael · Nov 3, 2012

So I'm a little confused. I keep reading some threads where people are saying that the b235r pistons can't handle anything over 300hp (crank) because the pistons are weak. Then I see some threads where people with later model aeros are running 300+hp on stock internals with no problems. So what's the deal? Were the early model 99-2002 pistons weaker then more current model years like 2004-2005?

I have a 2005 Aero and I'm getting a little concerned about going stage 3 and my car running over 300hp if it's just going to crap out on me down the road. My last car was an 06 STi and I went thru the whole cracked ringland problem and that was a major headache. I would hate for something similar to happen with my Aero.

Can anybody give me a breakdown on how safe it is to run a little over 300hp in a 05 Aero?

Thanks

whyyousaab · Nov 3, 2012

the T7 engines b205r b235r use thinner pistons that do suck and tend to brake over 300 hp. You can buy forged pistons that will withstand anything you can throw at it but they are 600+ installation..

brewtide · Nov 3, 2012

I was running around 280hp on the stockers, and I'll assume that my MAF was a bit wonky or something, but the issue on the stock pistons is in fact, generally, the ring lands as you stated. Some people have the entire piston shatter into dust, as the alternative.

Personally, if this was 'the car' that I owned, I'd stay stage 1 / 2 and drive it. Stage 3, in my personal opinion, is a bit too risky for a stage 3 tune, but some people get away with it. I imagine a very nice tune and knowledge of a fully functioning MAF, DI, etc etc, and you would be alright.

Mine now has JE's in it; Doing the work yourself isn't that bad, and if you decide to go that route, it's a lot cheaper to just put some pistons in the block before you go and possibly wreck the bores.

Some people drop the older b234 , stronger (heavier) pistons in the car, but they carry their whole new problem set (heavier, lots of mix and match aspects) or simply mount up an entire b234 bottom end -- In the end, it's easier to stay stage 1,2 and enjoy it, or get some wossner / je's and just 'do it'.

After that, the engine can handle quite a bit of power, as long as you provide fueling and tuning!

Good luck,
Benjamin

whyyousaab · Nov 4, 2012

Do b234r pistons fit into the 235r?

rabbit · Nov 4, 2012

I typically won't tune a b235r past my stage 3. It's kinda a grey area past that as far as reliability, but everyone agrees they pistons will melt if gone too far. Personally, I'd say 325 crank as long as its got a healthy afr, and everything is well in spec and its continuously monitored.

TankTak · Nov 4, 2012

never really paid any attention to this but what engine and pistons would my car have?
2002 9-5 Linear? and which would the Aero have?

brewtide · Nov 4, 2012

Same pistons as the Aero; b235 pistons. The 'r' engine in the aero is basically 3 different changes from the standard b235 engine, one of which I believe changes in later years even: td04 turbo vs. gt-17, the different software map in the ecu, and slightly different exhaust valves (sodium filled in the aero, vs NOT in the non aero (for an insane price...))...

Cheers,
Benjamin

paolo · Nov 6, 2012

You won't be running over 300hp with a stage 3 tune. Depending on tuner I'd say more like 285 290 tops. Unless you have a decent intercooler and a really nice tune you'll be lucking to see 300 consistently.
You're pistons will be ok at 300hp. Stop worrying and enjoy a stage 3. All you'll need is a tune, 3.5 bar fpr and a 3 inch down pipe.

Im running a stage 3 on an Aero with 208k miles and always give it beans.....

Jssaab · Nov 6, 2012

paolo said:
You won't be running over 300hp with a stage 3 tune. Depending on tuner I'd say more like 285 290 tops. Unless you have a decent intercooler and a really nice tune you'll be lucking to see 300 consistently.
You're pistons will be ok at 300hp. Stop worrying and enjoy a stage 3. All you'll need is a tune, 3.5 bar fpr and a 3 inch down pipe.

Im running a stage 3 on an Aero with 208k miles and always give it beans.....

Yeah Stage III is 290 crannk tops, you can go 300 WHP with stock pistons and a good tune with AFR monitiored. I did for years..

You cannot put 234 pistons in the engine, you need rods and crank as well. And 234 pistons in a 235 with T7 head will reduce your compression and reduce HP.

B235r weak pistons?

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